Solder placement nozzle with inert cover gas and inert gas bleed

Abstract

A nozzle assembly is shown for depositing solder onto a series of conductive surfaces such as the mounting pads of a surface mount integrated circuit board. The nozzle assembly includes a nozzle head which has an interior bore for receiving an elongate heat source. The nozzle head also includes an orifice for receiving solid solder fed within the interior bore to contact the elongate heat source. The interior bore terminates in a solder reservoir for molten solder which is fed within the inteiror bore to contact the elongate heat source. The molten solder is dispensed through a tip opening to deposit uniform amounts of solder on each pad. A source of bleed gas is supplied to the interior of the assembly to protect the component parts and excluse oxygen from the interior of the assembly. A cover gas is also supplied to the solder site to reduce oxidation of the moltent solder and reduce the amount of flux required.

I claim: 
     
       1. A nozzle assembly of the type which includes a heated metal tip of a soldering iron for depositing solder onto a series of conductive surfaces, the nozzle assembly comprising: a nozzle mount supportable above the conductive surface to be soldered, the nozzle amount having a length and having an internal bore sized to receive the heated metal tip of a soldering iron;   a nozzle head formed of a non-conductive plastic material removably mounted on the nozzle mount, the nozzle head having a solder feed orifice and having an interior bore sized to receive a portion of the length of the nozzle mount, thereby allowing the heated metal tip of the soldering iron to extend at least partly within the interior bore of the nozzle head for contacting solid solder fed within the interior bore through the solder feed orifice, the interior bore of the nozzle head including a solder reservoir for molten solder, the reservoir terminating in a tip opening for depositing molten solder onto a conductive surface; and   bleed gas means for supplying a bleed gas to the internal bore of the nozzle mount, past the heated metal tip of the soldering iron, and to the interior bore of the nozzle head to cool the nozzle assembly and exclude oxygen in the surrounding air form entering the nozzle assembly.   
     
     
       2. The nozzle assembly of claim 1, wherein the bleed gas means includes a bleed gas port provided in the nozzle mount which communicates with the interior bore of the nozzle mount, the bleed gas port being connected with a bleed gas source. 
     
     
       3. The nozzle assembly of claim 2, wherein the bleed gas source is a source of nitrogen gas. 
     
     
       4. A nozzle assembly of the type which includes a heated metal tip of a soldering iron for depositing solder onto a series of conductive surfaces, the nozzle assembly comprising: a nozzle mount supportable above the conductive surface to be soldered, the nozzle mount having a length and having an internal bore sized to receive the heated metal tip of a soldering iron;   a nozzle head formed of a non-conductive plastic material removably mounted on the nozzle mount, the nozzle head having a solder feed orifice and having an interior bore sized to receive a portion of the length of the nozzle mount, thereby allowing the heated metal tip of the soldering iron to extend at least partly within the interior bore of the nozzle head for contacting solid solder fed within the interior bore through the solder feed orifice, the interior bore of the nozzle head including a solder reservoir for molten solder, the reservoir terminating in a tip opening for depositing molten solder onto a conductive surface; and   bleed gas means for supplying a bleed gas to the internal bore of the nozzle mount, past the heated metal tip of the soldering iron and to the interior bore of the nozzle head to cool the nozzle assembly and exclude oxygen in the surrounding air from entering the nozzle assembly;   cover gas means for supplying a cover gas to the exterior of the nozzle tip as molten solder is being deposited through the tip opening to inhibit oxidation of the solder, the cover gas means comprising at least one internal passageway provided in the body of the nozzle head isolated from the interior bore thereof.   
     
     
       5. The nozzle assembly of claim 4, wherein the at least one internal passageway provided in the body of the nozzle head is connected to an extension tube which extends downwardly from the nozzle head in the direction of the tip opening of the nozzle head. 
     
     
       6. The nozzle assembly of claim 5, wherein the cover gas is an inert gas. 
     
     
       7. The nozzle assembly of claim 6, wherein the cover gas is nitrogen gas.